偏心管翅式相变储热单元性能强化的模拟

Numerical Simulation on Performance Enhancement of Eccentric Fin- tube Latent Heat Storage Unit

对管翅式相变储热单元进行了二维非稳态模拟研究。在考虑自然对流与外管传热的情况下对比研究了同心管翅、偏心管翅以及翅片接触外管三种储热单元的传热特性。考虑了内管壁温度、外管材料、翅片厚度对储热性能的影响。结果表明,与采用同心管翅时相比,由于自然对流的影响,偏心管翅储热单元有效削弱了固-液界面分布不均匀现象,完全融化时间减少了29.3%,而当翅片接触金属外管时,通过翅片的传热外管温度迅速升高,增大了换热面积,完全融化时间减少了近49.3%。可见,翅片接触外管储热单元不仅削弱了自然对流引起固-液界面分布不均匀现象,而且利用了外管的传热,强化了储热换热性能。

Two dimensional unsteady - state modeling has been performed on the heat transfer behavior of three latent heat storage unit made of concentric tube with fins and two eccentric tubes with fins. Natural convection and the conductivity from outer tube was considered in the modeling. Effects of various factors including the wall temperature from inner tube, outer tube material and fin thickness were examined. The results showed that, compared with the phase change material（PCM） melting time of the concentric tube with fins, the PCM melting time of eccentric tube with fins was reduced by 29.3%. And the reason was that with the effect of natural convection, the nonuniform distribution of solid - liquid interface could be weakened by using eccentric tube with fins. Upon contact with metal outer tube, the outer tube tempera- ture rised quickly through heat transfer from the fins which caused the increasing of heat exchange surface area, and the PCM melting time was reduced by 49.3%. In a conclusion, the eccentric tube contacting with outer tube by fins can not only weakened the nonuniform distribution of solid - liquid interface, but also enhanced latent heat storage performance through heat transfer from outer tube.